4 year child having rough patch on lower spine. Looking like bruise. What should be done?

Hello. I am wondering about a little rough patch of skin my 4 year old has along her lower spine. It has been there since birth. Sometimes it is more noticeable than other times. It goes from something you can only find if you are feeling around for it, other times it looks like a bruise. Her spine there is very prominent and since it's always been there, I've just thought her spine pushed on her skin. Her spine is straight and seems pretty uniform. Her daycare teacher however has discovered it and is freaking out.

Dear Patient,
Thanks for your query.
It seems from the history that it might be a port wine stain .
Such lesions are common in children and the site is also the one mentioned.
They usually subside by 7-8 years of age. No treatment is required for them